1. Field of the Invention
The present invention relates to an edge emphasizing circuit. More specifically, the present invention relates to an edge emphasizing circuit which is applied to a video camera and performs edge emphasizing on each of pixels forming an image signal output from an imager.
2. Description of the Prior Art
In a conventional edge emphasizing circuit, when an edge emphasizing signal generated based on an image signal is superimposed on an image signal, amplitude of the edge emphasizing signal is varied depending upon light and shade of an image. More specifically, a gain is increased as to a high-luminance image and a gain is decreased as to a low-luminance image.
However, in the prior art, amplitude is not varied depending upon whether a portion to be corrected is an edge portion or a plane portion, and when noise is superimposed on the high-luminance image, the noise is emphasized. That is, in the prior art, there are problems that edge emphasizing becomes insufficient upon reducing the noise, and the noise is conspicuous upon enhancing the edge.